This invention relates to endotracheal devices and more particularly to a laser resistant endotracheal tube with a concealed laser reflection material that can be immediately exposed in response to a laser strike to the tube.
Endotracheal devices are well known for facilitating passage of gases into and out of the body. An endotracheal device is usually placed in a patient's trachea to administer anesthesia and to maintain a respiratory flow path while a patient is under anesthesia.
In many surgical procedures, especially when there is a need to perform a remote cutting operation, a laser is used to cut or remove some portion of tissue. Occasionally a laser beam is inadvertently directed toward an endotracheal tube, thereby concentrating a substantial amount of energy onto the tube. If such energy is not dissipated or redirected, the tube can be burnt through or otherwise damaged, causing discomfort or injury to the patient.
Some known endotracheal devices that dissipate or redirect laser energy to resist laser burn-through include absorption devices, absorption and reflection devices, and reflection devices.
Absorption devices require the laser light to be absorbed by the tube. To accomplish such absorption, a coating of metallic particles mixed with a polymer is bonded to the exterior of a flexible polymeric tube. When the laser strikes the coating, a small amount of light is deflected with the remainder being absorbed into the surrounding incident area. This type of laser-resistant tube is effective with low energy laser strikes and short time exposure to the laser beam.
Absorbing and reflecting endotracheal devices rely on a layer of highly reflective material, typically aluminum or copper, which is, in turn, covered by a coating of laser absorption material of the type previously described. These devices thus rely on the reflective metallic layer to reflect the portion of the laser beam that is not absorbed by the laser absorption coating but penetrates the coating.
Since an endotracheal tube must be flexible for intubation purposes, the reflective metallic layer must also be flexible. Thus, the metallic layer can be in the form of a spirally wound metallic tape or a mechanically corrugated or worked metal. Reflective metals in these forms usually have rough, nonconformal surface characteristics that are an agitant to the patient's trachea and other body parts contacted by the tube.
In some instances, the laser absorptive coating is applied over the laser reflective material and smooths the surface of the reflective material to reduce potential patient trauma due to tracheal contact with a rough, nonconformal surface.
The absorption and reflection type endotracheal device is usually adequate for low laser energy levels over short periods of time. Under more rigorous conditions the absorptive coating tends to char which reduces reflectivity of the laser energy and promotes absorption of more of the laser energy until the tube reaches a temperature that results in a burn-through.
Reflection devices for endotracheal tubes generally include a highly reflective material to laser wavelength light such as aluminum, silver, stainless steel or copper. The reflective material can cover or actually constitute the body of the endotracheal tube. A tube of this type is thus capable of withstanding relatively high energy for several minutes since a laser beam is reflected from the tube with only small amounts of laser energy being absorbed into the metal. However, since such tube also must be formed of a metallic tape or mechanically corrugated or worked metal, the reflective surface is a rough, nonconformal surface that is also an agitant to the patient's trachea and other body parts contacted by the tube.
It is thus desirable to provide an endotracheal device with a laser reflective capability having a tube cover that provides a smooth conformal surface to the endotracheal tube and does not inhibit the reflectivity of the laser resistant materials.